1. Field of the Invention
This invention relates to a foundation arrangement for securing a factory built structure having an underframe including steel beams, to a land site, and more particularly to such an arrangement which includes a concrete pad having pier structures adapted to support the beams.
2. Prior Art
Mobile homes and offices, recreational vehicles, and like factory built modular structures, hereinafter termed "modular buildings" generally employ underframes constructed about a pair of parallel spaced steel beams extending the length of the unit. The building's wheels are supported on axles which may be permanently or temporarily affixed under these frame members. When the buildings are to be permanently or semi-permanently located at a site they are jacked up to raise them off the wheels and piles of concrete blocks or the like are stacked under the frame members and the unit is then lowered onto these stacks. Various forms of tie-down straps may be secured in the surrounding soil or to an underlying concrete pad and joined to the frame to secure the unit against dislodgement from the frame supports under forces imposed by wind and the like. The piles of blocks are often hidden from view by skirts extending between the edges of the underside of the unit and the ground or pad.
These foundation arrangements were developed when mobile homes were seldom retained at a site for longer than a single season. Modern mobile homes are typically only mobile for the short period of time required to move them from a factory or sales lot to a permanent building site. In these relatively permanent structures such makeshift foundation arrangements are far from satisfactory. First, they are usually not very secure and the mobile homes frequently tip over in high winds. Second, in order that the axles may clear the ground the units must be elevated so that the door sills are high above the ground and stairs must be provided to these doors. Finally, the arrangement is often unsightly with the space between the pad and the building used for storage of miscellaneous objects.